Spatial Change in Groundwater Quality and Its Determinants in Irrigation Areas at Tarim Basin, Xinjiang
2022
YAN Zhiyun | ZENG Yanyan | ZHOU Jinlong | SUN Ying
【Objective】 This paper is to analyze the spatial change in groundwater quality and its determinants in irrigation areas in Tarim Basin in Xinjiang, in attempts to provide a baseline guidance for sustainable utilization of groundwater resources and alleviating groundwater pollution. 【Method】 The analysis was based on 1 292 groundwater quality measurement data, from which we analyzed the groundwater chemical composition and chemistry types using the descriptive statistical analysis method and the Piper trilinear diagram method. The groundwater quality was analyzed using the water quality index method, USSL diagram and Wilcox diagram; spatial variation in groundwater quality and its determinants were calculated using the Kriging interpolation, factor analysis and ion ratio methods. 【Result】 Groundwater quality in the gravelly inclined plain in front of the mountain was better than that in the fine soil plain in the middle and low reaches of the basin. Dissolution of rocks increased ion contents in the groundwater, and groundwater quality deteriorates gradually from the gravelly inclined plain to the fine soil plain. The soluble salt concentration of groundwater in irrigation areas was considerably high; ions in shallow groundwater precipitated due to evaporation, resulting in salt accumulation on the soil surface. The factors affecting groundwater quality are ranked in the order: single structured unconfined groundwater>confined groundwater>unconfined groundwater in confined area. 【Conclusion】 The groundwater quality in the irrigation areas was jointly affected by evaporation and mineral dissolution, the redox in original geology, and human activities, in addition to aquifer type, groundwater recharge-discharge, runoff and cation exchange.
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